so close yet so far

.gdbinit

@@ -0,0 +1,2 @@
+target remote localhost:1234
+file target/kernel/kernel.bin

Makefile

@@ -1,6 +1,12 @@
 run: bin
 	qemu-system-i386 -drive format=raw,file=target/boot.bin -monitor stdio
 
+run_kernelonly: compile_kernel
+	qemu-system-i386 -kernel target/kernel/kernel.bin -monitor stdio
+
+debug_kernel: compile_kernel
+	qemu-system-i386 -s -S -kernel target/kernel/kernel.bin
+
 clean:
 	rm -r ./target/
 	mkdir -p ./target/helpers
@@ -19,5 +25,5 @@ compile_bootloader:
 
 compile_kernel:
 	nasm -felf32 kernel/wrapper.asm -o target/kernel/wrapper.o
-	i686-elf-gcc -c kernel/kernel.c -o target/kernel/kernel.o -std=gnu99 -ffreestanding -O2 -Wall -Wextra
-	i686-elf-gcc -T kernel/linker.ld -o target/kernel/kernel.bin -ffreestanding -O2 -nostdlib target/kernel/wrapper.o target/kernel/kernel.o -lgcc
+	i686-elf-gcc -g -c kernel/kernel.c -o target/kernel/kernel.o -std=gnu99 -ffreestanding -O2 -Wall -Wextra -mno-80387 -mgeneral-regs-only -mno-red-zone
+	i686-elf-gcc -g -T kernel/linker.ld -o target/kernel/kernel.bin -ffreestanding -O2 -nostdlib target/kernel/wrapper.o target/kernel/kernel.o -lgcc

bootloader/main.asm

@@ -136,9 +136,6 @@ mov ch, 0b00100000
 mov cl, 0b00000000
 int 0x10
 
-mov bl, dl
-call puthex
-
 ; reset disk system
 mov ah, 0x00
 ; mov dl, DISK_ID

kernel/inline_asm.c

@@ -0,0 +1,44 @@
+#ifndef INLINE_ASM_C
+#define INLINE_ASM_C
+
+#include <stdint.h>
+
+static inline void outb(uint16_t port, uint8_t val) {
+    asm volatile ( "outb %0, %1" : : "a"(val), "Nd"(port) );
+}
+
+static inline uint8_t inb(uint16_t port) {
+    uint8_t ret;
+    asm volatile ( "inb %1, %0"
+                   : "=a"(ret)
+                   : "Nd"(port) );
+    return ret;
+}
+
+static inline void lidt(void* base, uint16_t size)
+{   // This function works in 32 and 64bit mode
+    struct {
+        uint16_t length;
+        void*    base;
+    } __attribute__((packed)) IDTR = { size, base };
+ 
+    asm ( "lidt %0" : : "m"(IDTR) );  // let the compiler choose an addressing mode
+}
+
+/** issue a single request to CPUID. Fits 'intel features', for instance
+ *  note that even if only "eax" and "edx" are of interest, other registers
+ *  will be modified by the operation, so we need to tell the compiler about it.
+ */
+static inline void cpuid(int code, uint32_t *a, uint32_t *d) {
+    asm volatile("cpuid":"=a"(*a),"=d"(*d):"a"(code):"ecx","ebx");
+}
+
+/** issue a complete request, storing general registers output as a string
+ */
+static inline int cpuid_string(int code, uint32_t where[4]) {
+    asm volatile("cpuid":"=a"(*where),"=b"(*(where+1)),
+                "=c"(*(where+2)),"=d"(*(where+3)):"a"(code));
+    return (int)where[0];
+}
+
+#endif //INLINE ASM_C

kernel/interrupts.c

@@ -0,0 +1,108 @@
+#ifndef INTERRUPTS_C
+#define INTERRUPTS_C
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include "memory.c"
+#include "terminal.c"
+#include "inline_asm.c"
+
+typedef struct idt_entry_struct {
+   uint16_t offset_1; // offset bits 0..15
+   uint16_t selector; // a code segment selector in GDT or LDT
+   uint8_t zero;      // unused, set to 0
+   uint8_t type_attr; // type and attributes, see below
+   uint16_t offset_2; // offset bits 16..31
+} idt_entry;
+
+struct interrupt_frame {
+    uint32_t esp;
+    uint32_t ss;
+    uint32_t gs;
+    uint32_t fs;
+    uint32_t es;
+    uint32_t ds;
+    uint32_t ebp;
+    uint32_t edi;
+    uint32_t esi;
+    uint32_t edx;
+    uint32_t ecx;
+    uint32_t ebx;
+    uint32_t eax;
+    uint32_t eip;
+    uint32_t cs;
+    uint32_t eflags;
+};
+
+idt_entry IDT[256];
+int count = 1;
+
+void interrupt_new_handler(int intnum, void (*handler)(struct interrupt_frame*)) {
+    uint32_t handler_address = (uint32_t) handler;
+    IDT[intnum].offset_1 = (uint16_t) (handler_address & 0xffff);
+    IDT[intnum].selector = 0x08;
+    IDT[intnum].zero = 0;
+    IDT[intnum].type_attr = 0b10001110; // Active, privilege level 00, storage segment = 0; 32 bit interrupt gate
+    IDT[intnum].offset_2 = (uint16_t) ((handler_address & 0xffff0000) >> 16);
+}
+
+void kb_init() {
+    uint8_t mask = inb(0x21);
+
+    mask = mask & ~(1 << 1);
+
+	outb(0x21 , mask);
+}
+
+__attribute__((interrupt)) void keyboard_handler(struct interrupt_frame* frame) {
+    outb(0x20, 0x20);
+
+    char* result = "XXXXXX";
+    itoa(frame->eip, result, 16);
+    terminal_writestring(result);
+}
+
+void interrupt_init() {
+    /* ICW1 - begin initialization */
+	outb(0x20, 0x11);
+    outb(0xA0, 0x11);
+
+    /* ICW2 - remap offset address of IDT */
+    outb(0x21, 0x20);
+    outb(0xA1, 0x82);
+
+    /* ICW3 - setup cascading */
+    outb(0x21, 0x00);
+    outb(0xA1, 0x00);
+
+    /* ICW4 - environment info */
+    outb(0x21, 0x01);
+    outb(0xA1, 0x01);
+
+	/* mask interrupts */
+	outb(0x21 , 0xff);
+	outb(0xA1 , 0xff);
+
+    interrupt_new_handler(0x21, keyboard_handler);
+
+    uint16_t size = (sizeof(idt_entry) * 256);
+
+    terminal_writestring("Size = 0x");
+    char* result = "XXXXX";
+    itoa(size, result, 16);
+    terminal_writestring(result);
+
+	lidt(IDT, size);
+
+    kb_init();
+
+    uint8_t mask = inb(0x21);
+
+    terminal_writestring(" mask = 0b");
+    result = "XXXXXXXX";
+    itoa(mask, result, 2);
+    terminal_writestring(result);
+}
+
+#endif //INTERRUPTS_C

kernel/kernel.c

@@ -1,10 +1,3 @@
-#include <stdbool.h>
-#include <stddef.h>
-#include <stdint.h>
- 
-#include "terminal.c"
-#include "memory.c"
-
 /* Check if the compiler thinks you are targeting the wrong operating system. */
 #if defined(__linux__)
 #error "You are not using a cross-compiler, you will most certainly run into trouble"
@@ -12,15 +5,25 @@
  
 /* This tutorial will only work for the 32-bit ix86 targets. */
 #if !defined(__i386__)
-#error "This tutorial needs to be compiled with a ix86-elf compiler"
+#error "This kernel needs to be compiled with a ix86-elf compiler"
 #endif
 
-struct person {
-	long id;
-	int age;
-	char gender;
-};
- 
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "terminal.c"
+#include "memory.c"
+#include "interrupts.c"
+
+static inline bool are_interrupts_enabled() {
+    unsigned long flags;
+    asm volatile ( "pushf\n\t"
+                   "pop %0"
+                   : "=g"(flags) );
+    return flags & (1 << 9);
+}
+
 void kernel_main(void) 
 {
 	/* Initialize terminal interface */
@@ -45,11 +48,17 @@ void kernel_main(void)
 	memory_str[6] = 0;
 
 	char* management_str = alloc(sizeof(char) * 13);
-	for (int i = 0; i < 12; i++) {
-		management_str[i] = " management!"[i];
+	for (int i = 0; i < 13; i++) {
+		management_str[i] = " management!\n"[i];
 	}
-	management_str[12] = 0;
+	management_str[13] = 0;
 
 	terminal_writestring(memory_str);
 	terminal_writestring(management_str);
+
+	terminal_writestring((are_interrupts_enabled())? "Interrupts!\n": "No interrupts :(\n");
+
+	interrupt_init();
+
+	while(true) {}
 }

kernel/memory.c

@@ -1,9 +1,13 @@
+#ifndef MEMORY_C
+#define MEMORY_C
+
 #include <stddef.h>
 
-void* _curr_end = (void*) 0x10000;
+void* _curr_end = (void*) 0x200000;
 
 void* alloc(size_t size) {
     void* thanks_jp = _curr_end;
     _curr_end += size;
     return thanks_jp;
-}
+}
+#endif // MEMORY_C

kernel/terminal.c

@@ -1,3 +1,6 @@
+#ifndef TERMINAL_C
+#define TERMINAL_C
+
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -89,4 +92,30 @@ void terminal_write(const char* data, size_t size) {
  
 void terminal_writestring(const char* data) {
 	terminal_write(data, strlen(data));
-}
+}
+
+char* itoa(int value, char* result, int base) {
+	// check that the base if valid
+	if (base < 2 || base > 36) { *result = '\0'; return result; }
+
+	char* ptr = result, *ptr1 = result, tmp_char;
+	int tmp_value;
+
+	do {
+		tmp_value = value;
+		value /= base;
+		*ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
+	} while ( value );
+
+	// Apply negative sign
+	if (tmp_value < 0) *ptr++ = '-';
+	*ptr-- = '\0';
+	while(ptr1 < ptr) {
+		tmp_char = *ptr;
+		*ptr--= *ptr1;
+		*ptr1++ = tmp_char;
+	}
+	return result;
+}
+
+#endif //TERMINAL_C

kernel/wrapper.asm

@@ -54,6 +54,10 @@ _start:
 	; stack (as it grows downwards on x86 systems). This is necessarily done
 	; in assembly as languages such as C cannot function without a stack.
 	mov esp, stack_top
+
+	mov al, 0xff
+	out 0xa1, al
+	out 0x21, al
  
 	; This is a good place to initialize crucial processor state before the
 	; high-level kernel is entered. It's best to minimize the early
@@ -71,6 +75,7 @@ _start:
 	; stack since (pushed 0 bytes so far) and the alignment is thus
 	; preserved and the call is well defined.
         ; note, that if you are building on Windows, C functions may have "_" prefix in assembly: _kernel_main
+	sti
 	extern kernel_main
 	call kernel_main